How to Pollinate Onion

(Allium cepa)

Onion, also known as Garden onion, Common onion

The onion primarily relies on bees for pollination. Known for its vibrant blossoms and enticing scent, this plant effectively attracts bees, its main pollinators. As they collect nectar, their bodies brush against the pollen-laden anthers, leading to successful pollination. Timing is crucial, as pollination typically occurs in pristine weather during midday when bees are most active.

Which Pollinators are Suitable for Onion?

Bloom Time

Summer

Primary pollinators

Bees

Potential pollinators

Beetles, Butterflies

How Does Pollination Occur in Onion?

Onion's flowers are hermaphroditic, existing in spherical cluster formations known as umbels, predominantly colored white. Each individual flower houses six purple anthers, facilitating the plant's pollination process.

Pollination in onion generally occurs through cross-pollination by insects, but self-pollination is also possible within an umbel.

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How Can You Enhance the Pollination of Onion?

Plant Diversity

Plant a variety of flowering plants with different colors, shapes, and flowering times in the garden or farm. Bees, beetles, and butterflies are all attracted to flowering plants for nectar and pollen. Providing a range of options can increase the likelihood of attracting these pollinators.

Water Sources

Provide small, shallow water sources around the farming area. Bees, beetles, and butterflies all require water, and providing this can help attract these pollinators to the area.

Pesticide Management

Minimize the use of pesticides or switch to organic and bee-friendly pesticides. Chemical pesticides can harm or even kill these pollinators, so reducing their use can help create a more pollinator-friendly environment.

Nesting Sites

Create or maintain natural habitats or nesting sites around the farming area. Many bees nest in undisturbed land or dead wood, while some beetles and butterflies require specific habitats for their larvae. Providing suitable nesting sites can help increase the population of these pollinators.

How Can You Determine if Onion has Been Pollinated?

Flowering

Onion produces flowers within spherical clusters called umbels. Successful pollination often coincides with regular and numerous flower development.

Seed Set

After successful pollination and fertilization, onion produces a fruiting body that contains black seeds, which are a clear indication of pollination.

Pollen Presence

White-yellowish pollen visible on the flowers points towards pollination activities. Bees and insects are common pollinators for onion.

Understanding Hand-Pollination in Onion

Difficulty

Normal

Duration

60 mins

What Tools are Necessary for Hand-Pollinating Onion?

Pollen Brush

A small, very soft brush used for gently collecting and depositing pollen; avoid a brush that's too coarse as it may damage the flowers.

Gloves

Disposable gloves to prevent contamination or damage from skin oils.

Label and Marker

For marking the flowers to track the process and prevent confusion.

What is the Optimal Time for Hand-Pollinating Onion?

Hand-pollination of onion is ideally carried out during mid-morning, as this is typically when the flowers are fully open and have pollen readily available. As for the growth cycle, the process must be carried out when the onion has fully bloomed, which often occurs in the late spring or early summer.

Steps to Hand-Pollinate Onion

Step1: Identify Suitable Flowers

Differentiate the male from the female flowers. These can all be found on the same plant, though the male flowers tend to bloom first. Male flowers usually contain visible, pollen-covered anthers, while female flowers have a stigma.

Step2: Collect Polllen

Gently collect the pollen from the anthers of a male flower with the pollen brush. Be careful not to damage the flowers in the process.

Step3: Transfer Pollen

Take your pollen-laden brush straight over to your selected female flower. Gently touch or brush the pollen onto the stigma of the female flower.

Step4: Label the Flower

‘Tag’ the pollinated flower with a label and mark the date of pollination. This will help you to monitor the flower's development and prevent confusion.

Step5: Monitor Progress

Over the coming days and weeks, keep an eye on the pollinated flowers for signs of successful pollination. These could include the flower wilting (which indicates that the pollen has been accepted and the flower is no longer needed), while the base of the flower (the ovary) could start to swell as fruit sets and starts to grow.

Why Aren't There Fruits on Onion Despite the Presence of Flowers?

Poor Flowering

If onion isn't producing enough flowers, consider providing more sun exposure, adequate water, and balanced plant nutrition.

Lack of Pollinators

Attract pollinators by planting diverse plants, providing bee-friendly habitats, or manually pollinate using a small brush.

Pest or Disease Issues

Treat pests or diseases promptly. They can drastically reduce pollination by damaging flowers or discouraging pollinators.